Level and density measurement using non-contact nuclear gauges

This paper reviews the basic principles of nuclear gauging, and provides clear definitions of many of the terms in common usage in connection with nuclear radiation sources and detectors. The application of the basic principles to the sensing of liquid density and liquid level is described. For each measurand some practical guidelines are given relating to good installation practice and required precautions. This paper was selected from many on this topic because of its accessibility to non-physicist readers. (Eds.)